This invention relates to a method for the separation of isotopes from isotopic mixtures. More specifically, this invention relates to a method for the separation and recovery of isotopes of actinide elements. Still more specifically, this invention relates to a method for the separation and recovery of isotopes of uranium and plutonium.
While the demand for energy continues to increase, the supply of fossil fuels to supply this energy continues to grow smaller. This situation has placed increased emphasis on developing alternative sources of energy. Nuclear-fueled power reactors provide at least one means for partially solving the energy crisis and preventing it from becoming chronic. However, additional power reactors both here and abroad will require the production of large quantities of fuel to supply them. Since most of these reactors will be fueled with uranium, additional facilities will be required in the future for uranium enrichment. Uranium comes in two isotopes, the common nonfissioning uranium-238 and fissioning uranium-235. To be useful in a reactor, a fuel must be provided that is "enriched" in uranium-235 to at least 3% rather than the 0.7% found in naturally occurring uranium.
To make this enrichment, it is necessary that the two isotopes be separated. Separation of the isotopes cannot be done by ordinary chemical methods, since the chemical properties of each are exactly the same. Instead, methods must be used which are based on differences in mass. A number of separation methods have been developed such as the gas centrifuge process, electromagnetic separation and thermal diffusion, which have either not been carried beyond the pilot-plant stage or have been used only for an interim period of time. Uranium enrichment is presently being carried out utilizing the gaseous diffusion process. However, because the present facilities are becoming inadequate and because gaseous diffusion requires an enormous capital investment and consumes large quantities of electrical power to carry out the separation process, a considerable effort is being made to develop new methods for enrichment.